Effect of interval training with modified speed on the development of some special physical characteristics and maximum aerobic speed for field hockey juniors Mohamed Ahmed Abd alla * Introduction and research problem: Excellence in field hockey depends on developing the components of the training situation because of their effective impact on the players’ performance during competition in this sport. Therefore, specialists seek to develop these components through the use of modern training methods and methods that rely on scientific foundations and theories related to the sports field and work on Solve all problems that players may face during training and competition. Physical and physiological variables play an important role and are among the main factors in achieving excellence and achievement for field hockey players, as performance during competitions is linked to these variables, and this performance varies according to multiple factors such as the nature of the competitor and the circumstances surrounding the competition. Therefore, the methods of implementing various tactical duties vary, whether defensive or offensive, with a rapid transition from attack to defense and vice versa, at high speeds, with continuous repetition during the competition, which depends on the efficiency of the aerobic and anaerobic energy production systems. Maximum aerobic speed is one of the indicators associated with aerobic performance, as this indicator combines both maximum oxygen consumption and exercise economy together in one factor, and many studies conducted on high-level athletes have proven that maximum aerobic speed is highly sensitive to the effects of Aerobic training has high validity for explaining individual differences in aerobic performance. Khaled Naeem and Mustafa Tantawi (2020) recommend using interval training at modified speed to develop some physical and physiological variables for athletes in various sports activities and for different age stages during different season periods. Through the previous presentation of the importance of interval training at modified speed in creating physiological, physical and health adaptations, it is considered an economical strategy in time, and also as a result of some legal amendments such as (Self-Pass), which led to an increase in the speed of the playing rhythm by increasing the shift between defensive and offensive tactical performances. Reducing pauses during competition, which increases the physical and physiological demands during the match, Search goal: The research aims to study the effect of interval training at modified speed on developing some special physical characteristics and maximum aerobic speed for field hockey juniors by identifying: 1- The effect of interval training at modified speed on the development of some special physical characteristics of field hockey juniors. 2- The effect of modified interval training on developing the maximum air speed of field hockey juniors. Research hypotheses: 1- Interval training at modified speed has a positive effect on the development of some special physical characteristics of field hockey juniors. 2- Interval training at modified speed has a positive effect on the development of some physiological variables, such as the maximum air speed of field hockey juniors. Research methodology: The researcher used the experimental method by following the experimental design for one group, using pre- and post-measurements, as it suits the type and nature of this research. Research population and sample: The research population is represented by field hockey juniors under (18 years old) in the Eastern Region Hockey Clubs who are registered with the Egyptian Hockey Federation for the 2020/2021 season. The research sample was chosen intentionally and included a number of (30) junior hockey players under 18 years old in the Sharkia Sports Club and registered with the Egyptian Hockey Federation, and they were divided. To (18) juniors as the experimental research sample and (10) juniors as an exploratory sample for the research to conduct the exploratory study and scientific transactions. A number of (2) juniors were excluded due to injury and irregularity in training. Recommendations: 1- Using interval training at modified speed to develop some physical and physiological variables for athletes in various sporting activities and for different age stages during different periods of the season.